Non-circular rigid containers house a wide variety of products and materials such as, for example, food products (e.g., without limitation, processed meat products), and are well known in the container and canning industries. Such containers are commonly made of a metallic material such as an aluminum alloy sheet metal, tin plated steel alloy sheet metal, steel alloy sheet metal or some other suitable metal. The containers include walls which form a non-circular opening which must be closed by a can end having a corresponding non-circular shape. It is desirable that the non-circular can end be easy to open and safe (i.e., devoid of sharp edges) when opened.
FIGS. 1 and 2 illustrate a conventional non-circular can end 1 which is generally rectangular. As shown, the can end 1 includes a recessed panel 3 defined by a vertical chuckwall 5 surrounding the periphery of the panel 3. A peripheral scoreline 7, which is contiguous with the base of the chuckwall 5, defines an opening section 9 which is intended to be drawn away or removed from the can end to provide access to its contents. To facilitate rupture of the scoreline 7 and opening of the opening section 9, an opener such as a pull tab 11, is typically mounted on the panel 3. As shown in FIG. 2, the pull tab 11 is typically riveted to the opening section 9 of the panel 3 at the middle of one of the short ends of the can end 1. A separate recessed finger well 13 is included to reach beneath the pull tab 11 in order to initiate rotation thereof.
As shown, the pull tab 11 (FIG. 2) and rivet 15 attaching the pull tab 11 to the recessed panel 3 are located along a major dimensional centerline axis 17 (in plan view), of the can end 1. See, e.g., U.S. Pat. Nos. 5,217,134; 5,252,019; 5,328,313; 5,462,396; and 5,688,094. For example, for non-cylindrical configurations other than square configurations, such center line axis 17 is disposed along the longer dimension of the can end 1. See, e.g., U.S. Pat. No. 5,217,134 (FIGS. 20, 21 and 27). The centerline axis 17 on which the rivet 15 is located divides the can end 1 into equal halves along its longer dimension and provides for placement of the pull tab 11 on the panel 3 coincident with such centerline axis 17 (FIG. 2).
However, when disposed in such a position, the scoreline 7 extends laterally away from the nose end of the pull tab 11 or generally perpendicular to the nose end of the pull tab 11, thereby requiring an unnecessarily high pulling force on the handle end of the pull tab 11 in order to fracture and continue severing the scoreline 7.
Accordingly, known non-circular can ends of this type frequently further include other features designed to affect the way in which they are opened and removed. For example, some non-circular can ends include projections or recesses around the periphery or transversely disposed on the end panel, in order to, for example, provide a more rigid panel structured to be removed without significant rolling thereof. See e.g., U.S. Pat. No. 5,252,019 (FIGS. 25, 26 and 27); see also, U.S. Pat. Des. Nos. 328,032; and 425,419. Another feature often included on such can ends is a mustache scoreline 19 (FIG. 1) adjacent the attachment rivet 15 on a product side of the can end 1. Such mustache scorelines are designed to facilitate initial rupture of the peripheral scoreline 7 defining the opening section 9 and to provide easy opening of the can end 1 closure without the pull tab 11 being accidentally torn off of the panel 3. See, e.g., U.S. Pat. Nos. 5,217,134; 5,252,019; 5,328,313; 5,462,396; and 5,688,094.
For example, U.S. Pat. No. 5,252,019 entitled “Convenient-Feature Non-Circular End Closure With Interrupted Panel Profiling” describes a “reverse handle-bar mustache” configuration of a back scoreline on the end wall panel. The “reverse handle-bar mustache” score includes leg portions each directed on opposite sides of the rivet to act as a fulcrum for lever action severance of the peripheral scoreline. However, while the mustache score may reduce the initial force required to fracture the scoreline, the disclosed can end and pull tab design nonetheless require rotating the pull tab until it engages the chuckwall and then using the chuckwall as a fulcrum to facilitate continued severance of the scoreline and opening of the can end. Additionally, disposing a mustache score on the product side of the can end requires a post score coating operation to protect the rigid container material that has been scored from oxidation when using a rigid container material that oxidizes.
It is, therefore, desirable to provide a non-circular can end which overcomes the aforementioned disadvantages.
Accordingly, there is room for improvement in non-circular can ends, in tooling used to manufacture non-circular end can ends and in conversion presses for converting shells into non-circular can ends.